title: Theoretical insight into the intrinsic ultrafast formation of cyclobutane pyrimidine dimers in UV-irradiated DNA: thymine versus cytosine.
abstract: The higher formation yields measured in the ultrafast photoinduced formation of cyclobutane thymine dimers (T<>T) with respect to those of cytosine (C<>C) are explained, on the basis of ab initio CASPT2 results, by the existence in thymine of more reactive orientations and a less efficient photoreversibility, whereas in cytosine the funnel toward the photolesion becomes competitive with that mediating the internal conversion of the excited-cytosine monomer.
authors.affiliation: Instituto de Ciencia Molecular, Universitat de València, Apartado 22085, ES-46071 Valencia, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Serrano-Pérez
authors.forename: Israel
authors.initials: I
authors.lastname: González-Ramírez
authors.forename: Pedro B
authors.initials: PB
authors.lastname: Coto
authors.forename: Manuela
authors.initials: M
authors.lastname: Merchán
authors.forename: Luis
authors.initials: L
authors.lastname: Serrano-Andrés
mesh_terms: D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004249:DNA Damage; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011740:Pyrimidine Dimers / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry*; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; D003596:Cytosine; D004247:DNA; D013941:Thymine